function transform(timeStr) {
    var tmp = timeStr.split(':'); // ['12', '01', '40']
    return `${tmp[0]}点${tmp[1]}分${tmp[2]}秒`;
}

console.log(transform('12:01:40')); // '12点01分40秒'
console.log(transform('6:11:30')); // '6点11分30秒'
